The invention relates to a device for the measurement and registration of the location, the position and/or the change of location or position of a rigid body in space upon employment of a field generator, preferably a magnetic field generator, arranged directly on the body or at an interval therefrom, with means independent of the body arranged at an interval from the field generator for determining the field flux or, respectively, the field flux change during a measurement, as well as with an electronic installation for the production and evaluation of electric signals arising upon a field flux or, respectively, a field flux change.
In the earlier German patent application No. P 27 15 106 (U.S. Pat. No. 4,197,855 issued Apr. 15, 1980), a device of the said type was proposed in which, for the determination of the field flux, a plurality of surface pairs arranged perpendicularly to one another are provided, whereby each surface pair contains a multitude of sensor elements.
The arrangement of such a surface structure is relatively bulky and heavy and, particularly upon employment in dental medicine, has the disadvantage when determining the exact position or, respectively, a change of position of a point of the lower jaw of a patient that the access to the mouth area of the patient is obstructed and, therefore, the introduction of chewing matter for a measurement of the chewing motion is rendered more difficult.
It has further become apparent that the signals which give information for a rotational movement are relatively small in this arrangement and, thus, difficult to evaluate, particularly when the magnetic field generator is located in the center of the pick-up system, because the differential signals are already very small here. The formation of further differential signals from the differential signals received leads to even smaller signals which, as a result of the background noise of the electronic system which is already present and cannot be avoided, can be evaluated only relatively poorly and imprecisely.
Moreover, in order to compensate the influence of the earth's magnetic field in this arrangement, a compensation circuit for the three planes of the field pick-ups is required which necessitates an additional circuit-technical outlay.